Flow generator



FIG. 1 is a perspective view showing a flow generator according to my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof; and,

FIG. 6 is a top view thereof.

The bottom view is not shown.

Where included, the use of stippling is intended to denote a difference in materials.

The broken lines shown in the figures represent portions of a flow generator that form no part of the claimed design. 

The ornamental design for a flow generator, as shown and described. 